According to corresponding findings of leading scientists, every other cow has subclinic mastitis. This means, for example, that in the Federal Republic of Germany alone, an economic loss of at least 5 million DMs per year is sustained. The agent of udder diseases is transmitted practically exclusively through the line channel opening. Therefore, for many years widely spread intensive efforts have been made to reduce the transmission agent by precise hygienic precautionary measures. These additional measures consist in particular in a very exact udder cleaning and drying of the teats with disposable paper towels prior to milking, disinfecting the milking tool between each cow, dipping the teats into a disinfecting solution after each milking operation and placing all cows on long-term antibiotics. In spite of these expensive hygienic measures which have been used for many years, the rate of new infections has not been appreciably reduced. This fact proves that the transmission of infections must take place indeed during the removal of milk from the udder. For this reason, the role of the milking machine in the transmission of mastitis lately appears in a new light and scientists all over the world now intensively refer to the milking machine as a mastitis transmitter. Newer examinations have proven that the milk, during a milking operation using a milking tool which is common today, flows in the milking tool not only away in one direction from the teat, but also more or less regularly flows back from the collecting piece toward the teats. This return flow can, as has been proven, transmit microorganisms from a diseased quarter of the udder onto the still healthy quarter of the same cow or the next cows to be milked. It is assumed that in this one must find the most frequent cause for the newly occurring mastitis infections. The return flow of milk is caused primarily by two mostly independent causes: By the pump action of the pulsating teat rubber and by the air penetration during mounting and removing of the milking tool and by infiltrated air at the head of the teat rubber.
Very undesirable cyclic vacuum variations inside of the milking cup are created during the milking operation in the pump supply line of the pulsating teat rubber, reinforced by the mass moment of inertia of the milk which is transported in the milking tool. Up to now, one has tried to avoid said pressure variations and the associated return flow of milk contacting the tip of the teat by providing an enlarged volume in a collecting piece. However, the milk is obviously converted into fine aerosols, this even more large the collecting piece is. Due to pressure differences in the individual milking cups, it can hereby be effected that said aerosols are accelerated to a speed of up to 20 meters per second against another teat and due to this high speed permeate directly through the healthy closing muscle. Such pressure differences occur in particular in the case of an alternate rhythm operation, as when one side closes, while the other side opens. Even more dangerous is the air infiltration, which may be caused by a poorly fitting milking tool or particularly easily toward the end of a milking operation when the udder is less full. The teat, when the air infiltration occurs at the teat rubber, is not endangered, but rather due to the pressure drop the remaining teats may be endangered. For this reason, a total separation of the milk discharge from the individual udder quarters (quarter milking machine) appears to be urgently needed.
Quarter milking machines according to the two-chamber principle have been known already for a long period of time for effecting a determination for breeding purposes of the distribution of the milk output of the individual quarters of a cow. In the case of the common quarter milking machines, in which as a collecting piece four suitably bent small pipes, with the nominal diameter of the milking hoses, are connected to one unit; however, enormous cyclic vacuum variations occur, which could result in vacuum peaks being reached almost up to the absolute vacuum. However, the teats have been mechanically damaged through this, for which reason such quarter milking machines are out of the question for continuous use in a milking operation.
In a different conventional quarter milking machine, the disadvantages of the strong cyclic vacuum variations are overcome by totally doing away with a pulsation (so-called one-chamber cup). However, such machines were unable to be successful, because based on the nonexisting pressure stimulation of the cow through the pulsation operation of the teat rubber, the milk output and the length of the lactation period of the cows dropped substantially in comparison with other standard machines.
A satisfactory quarter milking machine could be realized only after the system of the periodic air infiltration in the relief phase and a corresponding milking cup with a valve controlled by a pulsator was developed. Only based on this development did it become possible to abandon an otherwise needed damping volume, which was necessarily provided in the collecting piece.
In a collecting piece with only one milk discharge line, as they are common up to now, a blocking off of the vacuum can be achieved in a simple manner prior to or after applying the milking cup to the teat, by the discharge line having been closed off with the help of a simple hose clamp or with the help of a lock which is provided in the collecting piece and which works either automatically or manually. With this, it was possible with the help of one single lock to block off or apply the vacuum simultaneously to all four teats. However, in the case of a quarter milking machine, four milk discharge lines are provided. It is considered to be extremely annoying and particularly work-consuming, if at the start or at the end of the milking operation the vacuum must be applied or switched off separately in all four milk discharge lines.
Therefore, the basic purpose of the present invention is to provide a quarter milking machine collecting piece, which is as compact as possible and permits with the help of one single manipulation to apply the vacuum to all four milking cups.
This purpose is inventively attained by providing a collecting piece of the above-mentioned type, wherein the ends of the supply lines each terminate in one common first sliding surface, wherein a second sliding surface sealingly engages against the first sliding surface, wherein a number of discharge lines which correspond with the number of the supply lines are provided, the ends of which each lie in the second sliding surface and extend therethrough, wherein the first and the second sliding surface is rotatable or movable relative to one another and wherein the ends of the supply lines are arranged in relationship to the ends of the discharge lines such that in a first position of the two sliding surfaces, the ends of all supply lines are aligned with the ends of all discharge lines, and that in a second position of the two sliding surfaces the second sliding surface closes off the ends of all supply lines and the first sliding surface closes off the ends of all discharge lines.
As a result, it is possible with one single manipulation, through which the two sliding surfaces are moved or rotated relative to one another, either to connect the vacuum which exists on all discharge lines simultaneously to all milking cups or to disconnect same therefrom.
The collecting piece is preferably constructed in such a manner that a pulsator pressure distributor piece is constructed with a supply line to a milking cup and a supply line to the quarter piece for an intermittent operation or two supply lines to the distributor piece for an alternate rhythm operation on one of the sliding surfaces, preferably on the first sliding surface. From this results a particularly compact arrangement in that all milk discharge lines and also pulsator underpressure lines run together and are combined at the collecting piece.
An arrangement is considered as particularly preferable from a technological milking standpoint and from an udder health standpoint, with which both the underpressure from all milk discharge lines can be applied with one manipulation to the milking cup and also simultaneously with the same manipulation the pulsator pressure to all milking cups. This is achieved with the help of a collecting piece, which is designed such that the end of the one supply line to the pulsator pressure distributor piece for the intermittent operation or the ends of the two supply lines to the pulsator pressure distributor piece for the push-pull operation each terminate in the first sliding surface and that a number of connecting lines, which number corresponds with the number of the supply lines to the pulsator pressure distributor piece are provided with the pulsator, the end or ends of which each lie in the second sliding surface and extend therethrough, and that the end of the supply line or the ends of the supply lines are arranged in relationship to the end of the connecting line or the ends of the connecting lines such that these are aligned with one another in the first position of the two sliding surfaces and in the second position of the two sliding surfaces are each closed off by these.
A preferable development of the collecting piece can consist in the first and the second sliding surface each consisting of one circular disk, which can be rotated relative to one another.
An arrangement has also proven to be particularly strong and particularly well sealing, in which the first and the second sliding surface each consist of a conical surface, which while sliding on one another are rotatable relative to one another.
To reduce the friction of the two sliding surfaces on one another with a simultaneous good seal and to thus improve the handiness of the collecting piece, at least one of the two sliding surfaces is coated with a solid material which improves the sliding characteristic, preferably a polymer plastic. A coating with a polytetrafluoroethylene (Teflon) has proven to be particularly preferable.
In order to make the adjusting of the collecting piece to the first or second position, namely, the two sliding surfaces relative to one another easier, cooperating locking mechanisms are preferably constructed on the two sliding surfaces, which mechanisms engage with one another in the first and the second position of the sliding surfaces.
A particularly strong and compact design of the collecting piece is obtained by the collecting piece consisting of a first inverted cup-shaped part, the edge of which extends conically enlarging outwardly and on the inside of which there is constructed the first sliding surface, and of a second truncated-cone-shaped part, on the outer side of which there is constructed the second sliding surface.
It is particularly important that the collecting piece be constructed such that it does not permit the penetration of dirt, has as much as possible no cavities, in which milk can settle and that the collecting piece can still be easily disassembled in order to clean it. These requirements are achieved particularly with the help of a collecting piece of the above-mentioned type, which is designed such that in the bottom of the inverted cup-shaped part there is provided a push rod which extends concentrically in axial direction through said part, is initially tensioned outwardly by a spring and projects outwardly, that on the end of the push rod, which end lies on the inside, there is secured a pin which extends transversely with respect to said push rod, such that the push rod is axially movable, however, is guided fixed against a relative rotation, and that in the end of the truncated-cone-shaped part, which end faces the inverted cup-shaped part, there are constructed two guideways which receive the ends of the pin in form of a bayonet lock.
The adjustments for the first and the second position of the sliding surfaces to one another can in this case be easily achieved, by the guideways having two locking recesses which correspond with the first and the second rotary positions of the sliding surfaces.
An unintended disassembling of the collecting piece during a rotation of the parts of the collecting piece relative to one another can be avoided by the collecting piece being constructed such that the guideways each have between their inlet openings and the locking recesses for the first and the second rotary positions a stop in the form of an elevation in the cam surface such that the bayonet lock can be released only by an axial inward movement of the push rod and simultaneous rotation of the inverted cup-shaped part and of the truncated-cone-shaped part relative to one another.
As has already become known through the principle of the milking cup having a valve, in which dependent on the control by the pulsator pressure, atmospheric air is let into the inside of the milking cup in the relief cycle, said air infiltration can take place also below the milking cup or also on the collecting piece. A particularly favorable development can now be achieved by such a pressure relief valve being combined directly with the collecting piece. The arrangement is such that on the pulsator pressure distributor piece there is provided in the case of an intermittent operation one or, in the case of an alternate rhythm operation, two pressure relief valves, which each contains or contain a diaphragm initially tensioned on its one side by a spring and is connected with a supply line to the pulsator pressure distributor piece and which is connected on its other side to a movable closure plug, which at an underpressure in the pulsator line interrupts a connecting line, which connects the atmosphere to a supply line to the inside of a milking cup.
A different preferred development is characterized by providing on the pulsator pressure distributor piece in the case of an intermittent operation one or, in the case of an alternate rhythm operation, two pressure relief valves, which each consists or consist of a ball check valve, which on the one side is connected to a supply line to the pulsator pressure distributor piece and on the other side to all supply lines to the milking cups in an intermittent operation or with each of two supply lines to the milking cups in a two-cycle operation.